This invention relates to a wrap spring mechanism that is used as a brake. The wrap spring brake can be configured in a winch to brake a load when an input to the winch is not rotated.
Winches for moving loads are well known in the art. In some applications, winches are operated to move a load, such as moving a boat up and down on a boatlift. To elevate the boatlift, a wheel is rotated causing the rotation of a drum that winds a cable about the drum thereby causing the boatlift to rise. The cooperation of the wheel and drum are typically controlled by a ratchet with teeth engaged with a pawl. The pawl engages the teeth such that the boatlift is held in an elevated position to prevent the unwinding of the cable from the drum. As the wheel is rotated to move the boatlift upward, the pawl is moved over the teeth, typically producing a clicking noise common to winch designs.
In order to prevent the cable from unwinding, a brake pad is often employed to brake the winch. A simple winch design that does away with the pawl and teeth engagement, as well as a brake pad, and yet holds a load safely in an elevated position would be a useful improvement in the art.